Torque converters are frequently used in motor vehicles to transmit the torque from the engine to the transmission. A torque converter typically comprises three main components, namely, an impeller, a turbine wheel and a stator, which is supported between the impeller and turbine wheel. All parts are housed in a converter housing that is filled with hydraulic fluid.
The stator comprises a stator rim, which supports guide blades, and a one-way clutch typically mounted on the inner circumference of the stator rim. In general, the one-way clutch has an outer freewheel ring, which is rotationally fixedly joined to the stator rim, an inner freewheel ring, which rests in a rotationally fixed manner on a stator shaft that is attached to the transmission, and a one-way clutch mechanism disposed between them. The one-way clutch permits a rotation of the stator in relation to the stator shaft in only one relative direction of rotation and blocks it in the other direction of rotation.
One-way clutch mechanisms, such as ratchet freewheels (European Patent 0 525 126 B1), roller-type freewheels (German Patents 32 41 053 A1 and 195 32 923 C2) or sprag freewheels (European Patent 0 811 788 B1) are known. Unfortunately, these clutch mechanisms must be made of a plurality of separate elements, requiring a high level of manufacturing and assembly effort. Thus, for example, numerous spring-mounted jamming rollers are inserted in a roller-type freewheel between the two freewheel rings in pockets of the outer ring. The respective spring presses the jamming roller into contact with a grip roller associated therewith. Depending on the direction of rotation, the outer ring may be rotated relative to the inner ring or be blocked in a wedgelike manner.
German Patent Application 100 17 744 A1 (US 2001/0027649 A1) discloses a freewheel for a stator of a hydrodynamic torque converter including a blocking element carrier extending in the circumferential direction and formed from an element in the shape of a ring wheel. First and second blocking elements are bent out from the ring wheel in opposing axial directions and opposing circumferential directions. In a corresponding manner, the solid freewheel inner element and the solid freewheel outer element have sections situated opposite each other in which axially open recesses are formed using embossing techniques.
The axially protruding locking elements of the locking element carrier axially engage in these recesses. In addition, a plurality of indentations are formed on the perimeter of the locking element carrier, in which the freewheel inner element engages with assigned radially inward gripping clutch projections in order to obtain a rotationally fixed coupling between the locking element carrier and the freewheel inner element. The locking surfaces are oriented opposite each other so that they are exposed in opposing circumferential directions in order to cooperate with the locking elements assigned to each. In order to be able to support the axial shear forces on the stator primarily in the locking mode for the freewheel, an additional axial support element acting between the two elements may be provided. Unfortunately, the freewheel elements must be placed on the periphery of the stator, which may not be desirable in all cases.